The present invention relates generally to a heat transfer cell and manufacturing apparatus, and specifically to a heat transfer cell comprising a stack of plates each having upstanding fins whose leading and trailing edges enhance turbulent airflow to thereby improve heat exchange. The manufacturing apparatus provides for the formation of a plurality of generally regularly spaced apart upstanding fins along a web of metallic material.
In the past, various techniques have been employed for the formation and closing of fins on metallic webs for subsequent use in heat transfer cells. In the formation of such webs, gaps have been frequently found between the adjacent metallic layers forming the fins, with such gaps permitting air to become trapped therebetween and thereby effectively diminishing the heat transfer capability of the fins and hence the systems which are created which use such finned plates for the heat transfer cell. In copending and commonly assigned patent application Ser. No. 826,146, filed Jan. 27, 1992, a fin forming apparatus is disclosed which comprises a first endless chain and a second endless chain wherein the first chain has a plurality of supporting anvil links while the second chain has a plurality of work engaging, fin-forming male lugs extending outwardly and arranged to force metallic web portions between the anvil links to thereby accomplish fin-formation in a metallic web. Applicants have now developed a fin-forming apparatus comprising only a single endless chain having a plurality of generally equally spaced anvil links arranged therealong, thereby eliminating fin-forming male lugs present on a second endless chain. In such manner, heat conductive plates useable in heat transfer cells are efficiently produced.
Heat transfer cells are widely used in heating and ventilation systems of larger buildings, schools, shopping centers and the like. The cells function to conserve and use heat from warm air being expelled by transferring this heat to entering cold air. One popular type of cell construction is a stack of heat conductive metal plates where each plate has a plurality of parallel fins which act to form channels in which air travels and also provides structural stability to the stack. The fins of each immediately adjacent plate are usually disposed at about 90 degrees to the fins of the reference plate, and heat exchange occurs as warm air and cold air travel through the cell at 90 degrees to each other. In particular, heat from the warm air which is being expelled is transferred through the metal plate with which it is in contact to the opposite side of the plate which is in contact with incoming cold air to thereby add warmth to the incoming air prior to ambient or furnace introduction.
Prior art configuration of the leading edge portions and trailing edge portions of the upstanding fins generally has been smooth, and resultant air travel through the fin-formed channels has been non-turbulent. However, we have found that turbulent air travel through the channels results in greater heat transfer from expelled warm air to incoming cold air as well as reduced cross-contamination of incoming air and exiting air.